Fluorocarbon-based polymer coating films have been used extensively and are manufactured by making the surface of an Al substrate rough by means of a brush or chemical etching, then coating the rough surface with a primer or the like and then with a paint suspending fine particles of a fluorocarbon-based material such as polytetrafluoroethylene in ethanol or the like and then carrying out drying and baking at about 400.degree. C. for about one hour to fix the fluorocarbon-based polymer to the substrate surface of the material.
This method of manufacture is simple. However, since the polymer and substrate are bonded together merely by an anchor effect, there is a limit in the adhesion of the polymer to the substrate. The method is insufficient in view of such performance as mechanical strength as a method of manufacturing fluorocarbon-based coating films used for apparatus or the like requiring heat-resistant, weather-resistant and wear-resistant coating, for instance such electric apparatus as hot plates and rice cooking apparatus, vehicles and industrial apparatus etc.